Speaking at the Scottish Labour conference in Inverness, he will describe Conservatives at Westminster and the SNP at Holyrood as "divisive".

He is expected to say: "We need to build a new settlement and only Labour can do it. The answer lies not in going back but in a new settlement, appropriate for new times."

He will criticise the dominance of finance over industry and the "laissez-faire" deregulated economy, saying the Conservative-led UK Government offers more of the same.

"We succeed not when a few at the top do well but when everyone contributes to our country; understanding the principle that we have always believed: that our success depends on the forgotten wealth creators, the people who do the hours, put in the shifts, struggle to pay their bills and just want a government on their side, a government that brings us together as one nation," he is expected to say.

"It's not going to be easy. And we have to be clear about that. It's not just a question of waiting for a little bit of growth or hoping to return to how things were.

"It is about new, credible, concrete answers to the new problems our country faces. Not to the old problems that blighted Britain in the 1970s, 1980s or 1990s, but the problems that define our age."

His focus on a "one nation" approach will be made on the same day as the Scottish Labour party discusses the future for devolution.

In tune with other unionist parties, Labour is considering what position to take in the event of a No vote in the Scottish independence referendum in September next year.

In his speech, Mr Miliband is expected to criticise First Minister Alex Salmond.

"While we sketch a plan for our economic future, he spends his time drawing a line through the country," he will say.

"It's the same divisive politics that we've seen from the Conservatives, just for a different end.

"He divides between the people of Scotland and the rest of the United Kingdom. A narrow nationalism that somehow believes we're stronger apart than together, that is so obsessed with driving us apart, that it has no focus on the issues that really shape people's lives."

Mr Salmond's approach will lead a "race to the bottom", with cuts to corporation tax in an independent Scotland, he will say.

"A narrow nationalism that prays for Tory success so that he can convince people that the only way to get rid of the Tories is to get out of the UK," he will say.

"Praying for Tory success: have you ever heard such a self-serving, selfish, narrow-minded, blinkered, in it for yourself, divide and rule piece of nonsense?"

Mr Miliband is also expected to reflect on the death of Baroness Thatcher and the reaction to her funeral.

"We know how much pain the Tory governments of that time caused to communities in Scotland and the whole of the United Kingdom," he is expected to say.

"Despite my deep disagreements with what Lady Thatcher did, it was right to show respect because you can't preach the principle of one nation and then fail to uphold it in practice.

"That principle defines who I am, how I lead the Labour party and how we would seek to change the country together with the British people."